By Naomi Friedman, Staff Writer
A robotic probe, Philae, made a historic landing on a comet on Nov. 12.
Regardless of whether Philae will ever recover communication with Earth, its historic landing orchestrated by the European Space Agency (ESA) is a “big step for human civilization,” according to Jean-Jacques Dourdain, the head of the ESA.
Loud cheers erupted in the ESA’s mission control center when the first signals of a successful landing were received by the center in Darmstadt, Germany. Scientists of 20 different European nationalities have followed this 20-year project very closely.
Rosetta, Philae’s mother ship, was launched on March 2, 2004. Her spectacular accomplishment of positioning herself in orbit around the Comet 67P/Churyumov-Gerasimenko (67P) was recorded on Aug. 8, 2014. This four-billion-mile-long cruise that took ten years through the solar system to get up-close and personal with the comet has been programmed to perform a detailed study of 67P with both an orbiter and a lander module, Philae.
Made of ancient ice, dust and other materials, comets have always been subject to scientific curiosity. Indeed, they would have survived practically intact from the earliest days of the solar system.
Not only will this mission give insights on what comets are actually made of and how they behave, scientists ultimately hope it may provide clues as to how the solar system was formed and evolved.
In the past, spacecraft have only made short visits to comets, including one that flew past Halley’s Comet in 1986. Europe’s $1.62 billion Rosetta Project is expected to surpass previous missions and plans to remain near the comet for a lengthy period.
Rosetta makes history by being the first craft to settle into a close orbit around a comet, the first to land a probe onto one and is expected to become the first spacecraft to accompany a comet as it loops around the sun, according to the Wall Street Journal.
Philae separated from Rosetta on Nov. 12 and slowly drifted for approximately seven hours toward the comet’s surface. The landing was more difficult than planned, as the robotic probe experienced additional technical problems impeding it from landing on the first try.
“Maybe today we didn’t just land once but twice,” said Stephan Ulamec, the lander manager at the ESA. Philae managed to land safely, but its current position on the comet does not get enough sunlight to recharge Philae’s solar-powered backup batteries. Only 1.5 hours of sunlight out of the 12.4 hours it takes for the comet to make one complete rotation around the sun make it doubtful the battery will recover enough performance to complete the radio link, says the BBC. The Washington Post suggests that there might still be a chance that as the comet continues through the inner solar system, Philae may wake up and phone home.
As soon as Philae touched ground, it started analyzing 67P with its 10 instruments for on-the-spot analysis and its onboard laboratory. The probe drilled the surface to take samples and sent all the data back to orbiting Rosetta, who then sent it to Earth.
After 57 hours of work, Philae ran out of power and fell silent, entering into a potentially long cold sleep that started on Nov. 15 at 0036 GMT, notes a Scientific American article.
Philae, although extraordinary, was not the only focus of the mission. Rosetta in orbit around 67P is able to study the whole comet when Philae could only sample a small part of it.
“We still hope that at a later stage of mission, perhaps when we are nearer to the sun, that we might have enough solar illumination to wake up the lander and reestablish communication,” said Ulamec in a press conference. “This machine performed magnificently under tough conditions, and we can be fully proud of the scientific success Philae has delivered.”
The mission has been covered by two Twitter accounts run by the ESA. One represents the probe (@Philae2014), and the other tweets on behalf of Rosetta mother ship (@ESA_Rosetta). The ESA shares jokes, images and step-by-step accounts of the mission. Before leaving us for an unknown period of time, @Philae2014 tweeted: “@ESA_Rosetta I’m feeling a bit tired, did you get all my data? I might take a nap #CometLanding.”